This invention relates to the delaminating of mica "plates" into small "flakes" for use as additives in various industrial applications. As with most minerals, mica is mined and then processed into a form suitable for the intended use. Heretofore, this generally has involved "cleaning" of the mined mica, preliminary crushing of the ore and then separating the usable product from contaminants, unusable fines, etc., by milling or other time and energy consuming processes. For instance, in some of the prior art, time of processing is described as many hours or even days. The difficulty, energy required, and costs involved have been great and the yield of suitable product low with prior devices and processes.
Patents showing various processes noted in a preliminary search include: U.S. Pat. Nos. 3,416,740; 2,547,336; 3,432,030; 533,384; 2,999,649; 2,204,063; and British patent 1,222,508.
U.S. Pat. No. 3,416,740 to Hodgson appears to applicant to be the closest prior art. The impeller in the drawings of Hodgson is inclined at a much greater angle, has a number of holes in it, is fed by a pump, and specifies the use of a milling medium. The present invention uses no "medium", uses a fixed volume feed, has the impeller mounted at a much smaller angle to the drive shaft, uses a hexagonal delaminating chamber in one embodiment, and uses the heat of separation to produce steam for facilitating the process, all of which results in a more efficient and cost effective machine and process as will become apparent from the following detailed description.
The other patents cited show various older attempts to separate and refine clay, mica and TiO.sub.2 by involved processes requiring chemical treatment, high velocity agitation, and extensive grinding in aqueous solutions. The yield and power required to operate these systems have generally prevented them from becoming commercially successful.
The present invention permits continuous operation versus the batch operation of the prior art and also results in a reduction in horsepower and time required to produce a 250 percent increase in efficiency from reduction in horsepower and time required to produce one pound of finished product.